In the related art, as a door handle device for a vehicle, for example, a device described in JP2012-154119A (Reference 1) is known. The door handle device for a vehicle has a detection member (person detection IC), an antenna, and two electric wires (connection wires) connecting the door handle device for a vehicle and a drive control portion (ECU). The two electric wires are shared as a power supply for the detection member and a power supply (for driving) for the antenna. That is, when the antenna is not driven, a DC voltage is supplied from the ECU to the detection member via the two electric wires and when the antenna is driven, an AC voltage is supplied from the ECU to the antenna via the two electric wires. Particularly, it has been proposed to utilize an induced voltage (resonance voltage) of the antenna in order to avoid disconnection of the power supply to the detection member when driving the antenna.
However, in Reference 1, since the induced voltage of the antenna is utilized to supply power to the detection member, it is necessary to set the induced voltage to a rated voltage of the detection member or less. In this case, for example, if it is tried to suppress an output level of the antenna, a communication distance is shortened and convenience may be impaired.
Thus, a need exists for a door handle device for a vehicle which is not susceptible to the drawback mentioned above.